This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-326877, filed Oct. 26, 2000, the entire contents of which are incorporated herein by reference.
The present invention relates to a structure of an evacuation and inert gas introduction apparatus. The apparatus is suitable for a case where the air contamination in the reaction chamber must be suppressed to an extremely low level, such as in the case of a molecular asymmetric catalyst synthesizing device.
Molecular asymmetric catalysts have high activities, and therefore they are focused worldwide as one of the core techniques in material conversion. The molecular asymmetric catalysts are key materials for creating functional organic materials having new values. Recently, excellent molecular asymmetric catalysts are developed one after another. Although the number of molecular asymmetric catalytic reactions which have been made practical in industries is small at this point as compared to that of the microbial enzymatic techniques, which are of a traditional industry of Japan, it is expected that the number of such reactions will be increased with accelerating speed. It is highly possible that the molecular asymmetric catalysts are used widely, not only in the medical and agricultural chemicals production industries, but also in the filed of the materials science industry.
In a synthesizing process for a molecular asymmetric catalyst, if the same glass tube is used for both of a line for evacuating the reaction chamber (evacuation line) and a line for introducing an inert gas to the reaction chamber (inert gas introduction line), there may rise a problem of contaminating the inside of the reaction chamber as the air, and the like, leaks into the reaction room during the operation of switching from the evacuation step to the inert gas introduction step.
In order to solve such a problem, there has been proposed a structure in which an evacuation line and an inert gas introduction line are connected to a reaction chamber via a three-way cock (a cock having three ports). With such a structure, the evacuation step is switched quickly to the inert gas introduction step, and therefore it is possible to prevent the air from leaking into the reaction chamber. However, when a three-way cock is employed, it is feared that an inside plug is pushed out of the housing when a pressure is applied to the inside of the reaction chamber, and the interior of the reaction chamber is contaminated with air. Further, if the inside plug is popped out with great force, it causes another problem of safety.
The present invention has been proposed in consideration of the above-described problems regarding the conventional structure of the evacuation line and inert gas introduction line in a molecular asymmetric catalyst synthesizing apparatus.
According to the present invention, there is provided an evacuation and insert gas introduction apparatus, comprising:
an evacuation line connected to a vacuum pump;
an inert gas introduction line connected to a supply source of an inert gas;
a shared line connected to a reaction chamber; and
a three-way cock having a first port connected to the evacuation line, a second port connected to the inert gas introduction line and a third port connected to the shared line, for switching over between a state where the first port is connected to the third port and a state where the second port is connected to the third port, by changing a rotation angle of an inside plug thereof,
wherein the three-way cock has a structure in which a vacuum cavity is provided for a tip end of a housing and the inside plug is attracted towards the tip end of the housing by the vacuum cavity.
In the evacuation and inert gas introduction apparatus of the present invention, the line for evacuating the reaction chamber (evacuation line) and the line for introducing an inert gas to the reaction chamber (inert gas introduction line) are made up by different systems from each other, and these lines and the reaction chamber are connected via a three-way cock having the above-described structure. As the three-way cock is rotated, the switching between the evacuation state within the reaction chamber and the inert gas introduction state of the reaction chamber can be carried out quickly by one operation. In this manner, the leakage of the air into the reaction chamber, which may occur during the line switching operation, can be prevented.
Further, the three-way cock is equipped with a vacuum cavity decompressed to a vacuum, which is provided at a tip end thereof, and therefore there is no such a possible danger that the inside plug of the cock is pushed out when the interior of the reaction chamber is pressurized. Further, the pressure on a ground surface of the cock is maintained high, and therefore it is possible to surely prevent leakage from the ground surface when the interior reaction chamber is evacuated.
As a result of the above, it is possible to suppress the factor of the air contamination within the reaction chamber. Further, the evacuation and inert gas introduction apparatus of the present invention has an excellent safety in term of operation.
A preferable embodiment of the apparatus of the present invention has a structure in which:
the first and second ports of the three-way cock are arranged on one side of a lateral surface of the housing, to be in line in the direction of the rotation axis of the inside plug;
the third port is formed on the opposite side of the lateral surface of the housing; and
the inside plug has two through holes formed therein such as to cross with the rotation axis diagonally,
wherein a state where the first port is connected to the third port via one of the through holes and a state where the second port is connected to the third port via the other of the through holes are switched over therebetween by rotating the inside plug by an angle of 180 degrees.
Another preferable embodiment of the apparatus of the present invention has a structure in which:
the evacuation line is connected to a vacuum pump via a solvent trap.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.